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  1. #1
    Air Chunk is offline Aluminum
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    Default thread pitch and size

    Hello! I am rying to figure out the thread pitch and size of a valve stem , just like on your car tire where the valve cap goes . All I have is a metric thread pitch gauge and I come up with 8mm with a .8 thread pitch . But I am not too sure if it is not an american std pitch as I do not have a gauge to cross reference.


    What do you think the size is ???

    Thanks!

  2. #2
    rke[pler's Avatar
    rke[pler is offline Diamond
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    Quote Originally Posted by Air Chunk View Post
    Hello! I am rying to figure out the thread pitch and size of a valve stem , just like on your car tire where the valve cap goes . All I have is a metric thread pitch gauge and I come up with 8mm with a .8 thread pitch . But I am not too sure if it is not an american std pitch as I do not have a gauge to cross reference.
    Probably a Schrader valve:

    https://secure.wikimedia.org/wikiped...Schrader_valve

  3. #3
    magneticanomaly is offline Stainless
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    IMHO it is .305-32, not anyone's standard AFAIK. I have made screw-on chucks for them, to go with my collection of hand tire pumps (try to have one in each vehicle)
    I'd be interested in what you're making. I recently found that Midland Metal Mfg has these chucks, but brass with short thread engagement, instead of steel and long, not as nice or probably durable as I made. It was a PITA to single-point those internal threads. Need to make some more.

  4. #4
    Air Chunk is offline Aluminum
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    19/64 = 0.2969" 7.5406mm
    5/16 = 0.3125" 7.9375mm

    so .305 32 is not a standard tap is it ????

    Or am I missing something?

  5. #5
    DaveE907 is offline Titanium
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    This previous forum thread might be useful to you:

    How do you measure pitch diameter on a modified buttress thread?

  6. #6
    Air Chunk is offline Aluminum
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    Thanks for the insight and the thread link it helps.

  7. #7
    morsetaper2 is offline Titanium
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    If you can't find what you need i have the Tire & Rim Assoc Handbook at work. It has ALL the specs! If you need it tomorrow, PM me and I can send you a scan of Schrader Valve thread specs that will help you.

  8. #8
    morsetaper2 is offline Titanium
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    Quote Originally Posted by Air Chunk View Post
    Hello! I am rying to figure out the thread pitch and size of a valve stem , just like on your car tire where the valve cap goes .
    Thanks!
    Its most likely .305-32 as was stated by a prior poster. I got your PM, and sent you a scan of a section of the spec book back to your email.

    Ping me back by email or phone if you need addtl specs. The book is 100's of pages long, but what I sent should cover you.

    Mark

  9. #9
    Air Chunk is offline Aluminum
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    Morsetaper2,
    Thank You !

  10. #10
    ZAGNUT is offline Hot Rolled
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    i (should) have a .305"x32 tap i bought over 20 years ago to make custom valve caps for bikes. was faintly labeled with the size and "schrader". quick google search turned this up: Engineering Supplies - a) 0.305x32 UNS HSS Ground Thread Tap Schrader valve tap


    never tried it but 5/16"x32 might be close enough.

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